This project involves digital processing and computer interpretation in electrocardiography (ECG), various modalities of which are the most widely used diagnostic and prognostic tools in cardiovascular disease. In the U.S. up to 150 million routine diagnostic ECGs are performed annually. Ambulatory patients, patients being transported in emergency vehicles to the hospital, and patients in intensive care units are monitored by ECG. The ambulatory ECG and the signal-averaged ECG are used to estimate risk of sudden death from fatal cardiac rhythm disturbances. The exercise ECG is used to diagnose coronary disease. A workshop at the National Heart, Lung, and Blood Institute (NHLBI) published last year (of which J. Bailey was an organizer and co-author) proposed the creation of a national archive of ECG databases from studies conducted by public and academic medical centers, especially those funded by NHLBI. The ultimate goal of this archive would be raw digital ECG data and ancillary information (demographics, disease status, etc.) accessible by clinical investigators and epidemiologists over a high speed data link. As a first step, MSCL set up and currently maintains a public ECG Registry on a NHLBI website, where investigators can post their database or find out whats available and who to contact. The Framingham Heart Study, Wake Forest Medical Center, and the Syracuse Veterans Administration Medical Center were early contributors to the Registry. In FY99 a Scottish medical center and a German government agency have added postings. A singular application of ECG is heart rate variability (HRV), which reflects how the autonomic nervous system affects the heart. In collaborative, blind study with Walter Reed Army Medical Center and the U.S. Uniformed Health Services, HRV is being tested in teenage diabetics for sensitivity to autonomic neuropathy. In FY99, HRV was extracted from eleven subjects? ECG data; correlation with severity parameters (e.g. duration, hemoglobin A1c, Ur beta2 microglobulin) will require many more subjects before code- breaking and analysis. Also in FY99, a long term collaborative study of HRV in syncopal patients at the Childrens National Medical Center resulted in a paper published in the Journal of the American College of Cardiology; a paper on a follow-up study is in preparation. In collaboration with NHLBI and the Agency for Health Care Policy and Research, reports back to 1986 of different diagnostic modalities such as HRV, signal-average ECGs, and ejection fraction were reviewed and a meta-analysis performed to compare their abilities to predict long term risk in post myocardial infarction patients; this manuscript has been submitted. J. Bailey is chairman of the ECG Committee for the Association for Advancement of Medical Instrumentation. This committee supervises the work of six working groups (subcommittees) dealing with national and international medical device standards. Standards were written for ambulatory ECG devices, for cardiac monitors, and for signal-averaged ECG devices; these three documents were approved by the American National Standards Institute" and have been sent to the publisher. - syncope diabetes autonomic neuropathy electrocardiology databases